I'm pretty sure time is taken into consideration, and that a correctly solved problem solved to slow can result in a deduction of rating points. This is because the average time to solve is the benchmark against which you're being measured, and against which the problem itself is rated.
The question you may want to ask yourself is, rating adjustments aside, are you learning from the problems? Are they helping to improve your board vision and your game? If so, what's the sense in getting too worked up over what your tactics rating is? If losing a couple of rating points on a tactics puzzle ultimately helps you gain strength in your regular games isn't that a win?
Boy, this is the worst most depressing tactical exercises I have ever done. When my subscription up this will come into consideration
How can u deduct 10 over points for a correctly solved puzzle n only reward 1 to 3 point for a puzzled solved fast. This sucks!!